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<FONT color="green">001</FONT>    /*<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT>     * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT>     * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT>     * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT>     * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT>     * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT>     *<a name="line.8"></a>
<FONT color="green">009</FONT>     *      http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT>     * See the License for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT>     * limitations under the License.<a name="line.15"></a>
<FONT color="green">016</FONT>     */<a name="line.16"></a>
<FONT color="green">017</FONT>    <a name="line.17"></a>
<FONT color="green">018</FONT>    package org.apache.commons.math3.optimization.fitting;<a name="line.18"></a>
<FONT color="green">019</FONT>    <a name="line.19"></a>
<FONT color="green">020</FONT>    import java.util.Arrays;<a name="line.20"></a>
<FONT color="green">021</FONT>    import java.util.Comparator;<a name="line.21"></a>
<FONT color="green">022</FONT>    <a name="line.22"></a>
<FONT color="green">023</FONT>    import org.apache.commons.math3.analysis.function.Gaussian;<a name="line.23"></a>
<FONT color="green">024</FONT>    import org.apache.commons.math3.exception.NullArgumentException;<a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.commons.math3.exception.NumberIsTooSmallException;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.commons.math3.exception.OutOfRangeException;<a name="line.26"></a>
<FONT color="green">027</FONT>    import org.apache.commons.math3.exception.ZeroException;<a name="line.27"></a>
<FONT color="green">028</FONT>    import org.apache.commons.math3.exception.NotStrictlyPositiveException;<a name="line.28"></a>
<FONT color="green">029</FONT>    import org.apache.commons.math3.exception.util.LocalizedFormats;<a name="line.29"></a>
<FONT color="green">030</FONT>    import org.apache.commons.math3.optimization.DifferentiableMultivariateVectorOptimizer;<a name="line.30"></a>
<FONT color="green">031</FONT>    import org.apache.commons.math3.util.FastMath;<a name="line.31"></a>
<FONT color="green">032</FONT>    <a name="line.32"></a>
<FONT color="green">033</FONT>    /**<a name="line.33"></a>
<FONT color="green">034</FONT>     * Fits points to a {@link<a name="line.34"></a>
<FONT color="green">035</FONT>     * org.apache.commons.math3.analysis.function.Gaussian.Parametric Gaussian} function.<a name="line.35"></a>
<FONT color="green">036</FONT>     * &lt;p&gt;<a name="line.36"></a>
<FONT color="green">037</FONT>     * Usage example:<a name="line.37"></a>
<FONT color="green">038</FONT>     * &lt;pre&gt;<a name="line.38"></a>
<FONT color="green">039</FONT>     *   GaussianFitter fitter = new GaussianFitter(<a name="line.39"></a>
<FONT color="green">040</FONT>     *     new LevenbergMarquardtOptimizer());<a name="line.40"></a>
<FONT color="green">041</FONT>     *   fitter.addObservedPoint(4.0254623,  531026.0);<a name="line.41"></a>
<FONT color="green">042</FONT>     *   fitter.addObservedPoint(4.03128248, 984167.0);<a name="line.42"></a>
<FONT color="green">043</FONT>     *   fitter.addObservedPoint(4.03839603, 1887233.0);<a name="line.43"></a>
<FONT color="green">044</FONT>     *   fitter.addObservedPoint(4.04421621, 2687152.0);<a name="line.44"></a>
<FONT color="green">045</FONT>     *   fitter.addObservedPoint(4.05132976, 3461228.0);<a name="line.45"></a>
<FONT color="green">046</FONT>     *   fitter.addObservedPoint(4.05326982, 3580526.0);<a name="line.46"></a>
<FONT color="green">047</FONT>     *   fitter.addObservedPoint(4.05779662, 3439750.0);<a name="line.47"></a>
<FONT color="green">048</FONT>     *   fitter.addObservedPoint(4.0636168,  2877648.0);<a name="line.48"></a>
<FONT color="green">049</FONT>     *   fitter.addObservedPoint(4.06943698, 2175960.0);<a name="line.49"></a>
<FONT color="green">050</FONT>     *   fitter.addObservedPoint(4.07525716, 1447024.0);<a name="line.50"></a>
<FONT color="green">051</FONT>     *   fitter.addObservedPoint(4.08237071, 717104.0);<a name="line.51"></a>
<FONT color="green">052</FONT>     *   fitter.addObservedPoint(4.08366408, 620014.0);<a name="line.52"></a>
<FONT color="green">053</FONT>     *   double[] parameters = fitter.fit();<a name="line.53"></a>
<FONT color="green">054</FONT>     * &lt;/pre&gt;<a name="line.54"></a>
<FONT color="green">055</FONT>     *<a name="line.55"></a>
<FONT color="green">056</FONT>     * @since 2.2<a name="line.56"></a>
<FONT color="green">057</FONT>     * @version $Id: GaussianFitter.java 1422230 2012-12-15 12:11:13Z erans $<a name="line.57"></a>
<FONT color="green">058</FONT>     * @deprecated As of 3.1 (to be removed in 4.0).<a name="line.58"></a>
<FONT color="green">059</FONT>     */<a name="line.59"></a>
<FONT color="green">060</FONT>    @Deprecated<a name="line.60"></a>
<FONT color="green">061</FONT>    public class GaussianFitter extends CurveFitter&lt;Gaussian.Parametric&gt; {<a name="line.61"></a>
<FONT color="green">062</FONT>        /**<a name="line.62"></a>
<FONT color="green">063</FONT>         * Constructs an instance using the specified optimizer.<a name="line.63"></a>
<FONT color="green">064</FONT>         *<a name="line.64"></a>
<FONT color="green">065</FONT>         * @param optimizer Optimizer to use for the fitting.<a name="line.65"></a>
<FONT color="green">066</FONT>         */<a name="line.66"></a>
<FONT color="green">067</FONT>        public GaussianFitter(DifferentiableMultivariateVectorOptimizer optimizer) {<a name="line.67"></a>
<FONT color="green">068</FONT>            super(optimizer);<a name="line.68"></a>
<FONT color="green">069</FONT>        }<a name="line.69"></a>
<FONT color="green">070</FONT>    <a name="line.70"></a>
<FONT color="green">071</FONT>        /**<a name="line.71"></a>
<FONT color="green">072</FONT>         * Fits a Gaussian function to the observed points.<a name="line.72"></a>
<FONT color="green">073</FONT>         *<a name="line.73"></a>
<FONT color="green">074</FONT>         * @param initialGuess First guess values in the following order:<a name="line.74"></a>
<FONT color="green">075</FONT>         * &lt;ul&gt;<a name="line.75"></a>
<FONT color="green">076</FONT>         *  &lt;li&gt;Norm&lt;/li&gt;<a name="line.76"></a>
<FONT color="green">077</FONT>         *  &lt;li&gt;Mean&lt;/li&gt;<a name="line.77"></a>
<FONT color="green">078</FONT>         *  &lt;li&gt;Sigma&lt;/li&gt;<a name="line.78"></a>
<FONT color="green">079</FONT>         * &lt;/ul&gt;<a name="line.79"></a>
<FONT color="green">080</FONT>         * @return the parameters of the Gaussian function that best fits the<a name="line.80"></a>
<FONT color="green">081</FONT>         * observed points (in the same order as above).<a name="line.81"></a>
<FONT color="green">082</FONT>         * @since 3.0<a name="line.82"></a>
<FONT color="green">083</FONT>         */<a name="line.83"></a>
<FONT color="green">084</FONT>        public double[] fit(double[] initialGuess) {<a name="line.84"></a>
<FONT color="green">085</FONT>            final Gaussian.Parametric f = new Gaussian.Parametric() {<a name="line.85"></a>
<FONT color="green">086</FONT>                    @Override<a name="line.86"></a>
<FONT color="green">087</FONT>                    public double value(double x, double ... p) {<a name="line.87"></a>
<FONT color="green">088</FONT>                        double v = Double.POSITIVE_INFINITY;<a name="line.88"></a>
<FONT color="green">089</FONT>                        try {<a name="line.89"></a>
<FONT color="green">090</FONT>                            v = super.value(x, p);<a name="line.90"></a>
<FONT color="green">091</FONT>                        } catch (NotStrictlyPositiveException e) { // NOPMD<a name="line.91"></a>
<FONT color="green">092</FONT>                            // Do nothing.<a name="line.92"></a>
<FONT color="green">093</FONT>                        }<a name="line.93"></a>
<FONT color="green">094</FONT>                        return v;<a name="line.94"></a>
<FONT color="green">095</FONT>                    }<a name="line.95"></a>
<FONT color="green">096</FONT>    <a name="line.96"></a>
<FONT color="green">097</FONT>                    @Override<a name="line.97"></a>
<FONT color="green">098</FONT>                    public double[] gradient(double x, double ... p) {<a name="line.98"></a>
<FONT color="green">099</FONT>                        double[] v = { Double.POSITIVE_INFINITY,<a name="line.99"></a>
<FONT color="green">100</FONT>                                       Double.POSITIVE_INFINITY,<a name="line.100"></a>
<FONT color="green">101</FONT>                                       Double.POSITIVE_INFINITY };<a name="line.101"></a>
<FONT color="green">102</FONT>                        try {<a name="line.102"></a>
<FONT color="green">103</FONT>                            v = super.gradient(x, p);<a name="line.103"></a>
<FONT color="green">104</FONT>                        } catch (NotStrictlyPositiveException e) { // NOPMD<a name="line.104"></a>
<FONT color="green">105</FONT>                            // Do nothing.<a name="line.105"></a>
<FONT color="green">106</FONT>                        }<a name="line.106"></a>
<FONT color="green">107</FONT>                        return v;<a name="line.107"></a>
<FONT color="green">108</FONT>                    }<a name="line.108"></a>
<FONT color="green">109</FONT>                };<a name="line.109"></a>
<FONT color="green">110</FONT>    <a name="line.110"></a>
<FONT color="green">111</FONT>            return fit(f, initialGuess);<a name="line.111"></a>
<FONT color="green">112</FONT>        }<a name="line.112"></a>
<FONT color="green">113</FONT>    <a name="line.113"></a>
<FONT color="green">114</FONT>        /**<a name="line.114"></a>
<FONT color="green">115</FONT>         * Fits a Gaussian function to the observed points.<a name="line.115"></a>
<FONT color="green">116</FONT>         *<a name="line.116"></a>
<FONT color="green">117</FONT>         * @return the parameters of the Gaussian function that best fits the<a name="line.117"></a>
<FONT color="green">118</FONT>         * observed points (in the same order as above).<a name="line.118"></a>
<FONT color="green">119</FONT>         */<a name="line.119"></a>
<FONT color="green">120</FONT>        public double[] fit() {<a name="line.120"></a>
<FONT color="green">121</FONT>            final double[] guess = (new ParameterGuesser(getObservations())).guess();<a name="line.121"></a>
<FONT color="green">122</FONT>            return fit(guess);<a name="line.122"></a>
<FONT color="green">123</FONT>        }<a name="line.123"></a>
<FONT color="green">124</FONT>    <a name="line.124"></a>
<FONT color="green">125</FONT>        /**<a name="line.125"></a>
<FONT color="green">126</FONT>         * Guesses the parameters {@code norm}, {@code mean}, and {@code sigma}<a name="line.126"></a>
<FONT color="green">127</FONT>         * of a {@link org.apache.commons.math3.analysis.function.Gaussian.Parametric}<a name="line.127"></a>
<FONT color="green">128</FONT>         * based on the specified observed points.<a name="line.128"></a>
<FONT color="green">129</FONT>         */<a name="line.129"></a>
<FONT color="green">130</FONT>        public static class ParameterGuesser {<a name="line.130"></a>
<FONT color="green">131</FONT>            /** Normalization factor. */<a name="line.131"></a>
<FONT color="green">132</FONT>            private final double norm;<a name="line.132"></a>
<FONT color="green">133</FONT>            /** Mean. */<a name="line.133"></a>
<FONT color="green">134</FONT>            private final double mean;<a name="line.134"></a>
<FONT color="green">135</FONT>            /** Standard deviation. */<a name="line.135"></a>
<FONT color="green">136</FONT>            private final double sigma;<a name="line.136"></a>
<FONT color="green">137</FONT>    <a name="line.137"></a>
<FONT color="green">138</FONT>            /**<a name="line.138"></a>
<FONT color="green">139</FONT>             * Constructs instance with the specified observed points.<a name="line.139"></a>
<FONT color="green">140</FONT>             *<a name="line.140"></a>
<FONT color="green">141</FONT>             * @param observations Observed points from which to guess the<a name="line.141"></a>
<FONT color="green">142</FONT>             * parameters of the Gaussian.<a name="line.142"></a>
<FONT color="green">143</FONT>             * @throws NullArgumentException if {@code observations} is<a name="line.143"></a>
<FONT color="green">144</FONT>             * {@code null}.<a name="line.144"></a>
<FONT color="green">145</FONT>             * @throws NumberIsTooSmallException if there are less than 3<a name="line.145"></a>
<FONT color="green">146</FONT>             * observations.<a name="line.146"></a>
<FONT color="green">147</FONT>             */<a name="line.147"></a>
<FONT color="green">148</FONT>            public ParameterGuesser(WeightedObservedPoint[] observations) {<a name="line.148"></a>
<FONT color="green">149</FONT>                if (observations == null) {<a name="line.149"></a>
<FONT color="green">150</FONT>                    throw new NullArgumentException(LocalizedFormats.INPUT_ARRAY);<a name="line.150"></a>
<FONT color="green">151</FONT>                }<a name="line.151"></a>
<FONT color="green">152</FONT>                if (observations.length &lt; 3) {<a name="line.152"></a>
<FONT color="green">153</FONT>                    throw new NumberIsTooSmallException(observations.length, 3, true);<a name="line.153"></a>
<FONT color="green">154</FONT>                }<a name="line.154"></a>
<FONT color="green">155</FONT>    <a name="line.155"></a>
<FONT color="green">156</FONT>                final WeightedObservedPoint[] sorted = sortObservations(observations);<a name="line.156"></a>
<FONT color="green">157</FONT>                final double[] params = basicGuess(sorted);<a name="line.157"></a>
<FONT color="green">158</FONT>    <a name="line.158"></a>
<FONT color="green">159</FONT>                norm = params[0];<a name="line.159"></a>
<FONT color="green">160</FONT>                mean = params[1];<a name="line.160"></a>
<FONT color="green">161</FONT>                sigma = params[2];<a name="line.161"></a>
<FONT color="green">162</FONT>            }<a name="line.162"></a>
<FONT color="green">163</FONT>    <a name="line.163"></a>
<FONT color="green">164</FONT>            /**<a name="line.164"></a>
<FONT color="green">165</FONT>             * Gets an estimation of the parameters.<a name="line.165"></a>
<FONT color="green">166</FONT>             *<a name="line.166"></a>
<FONT color="green">167</FONT>             * @return the guessed parameters, in the following order:<a name="line.167"></a>
<FONT color="green">168</FONT>             * &lt;ul&gt;<a name="line.168"></a>
<FONT color="green">169</FONT>             *  &lt;li&gt;Normalization factor&lt;/li&gt;<a name="line.169"></a>
<FONT color="green">170</FONT>             *  &lt;li&gt;Mean&lt;/li&gt;<a name="line.170"></a>
<FONT color="green">171</FONT>             *  &lt;li&gt;Standard deviation&lt;/li&gt;<a name="line.171"></a>
<FONT color="green">172</FONT>             * &lt;/ul&gt;<a name="line.172"></a>
<FONT color="green">173</FONT>             */<a name="line.173"></a>
<FONT color="green">174</FONT>            public double[] guess() {<a name="line.174"></a>
<FONT color="green">175</FONT>                return new double[] { norm, mean, sigma };<a name="line.175"></a>
<FONT color="green">176</FONT>            }<a name="line.176"></a>
<FONT color="green">177</FONT>    <a name="line.177"></a>
<FONT color="green">178</FONT>            /**<a name="line.178"></a>
<FONT color="green">179</FONT>             * Sort the observations.<a name="line.179"></a>
<FONT color="green">180</FONT>             *<a name="line.180"></a>
<FONT color="green">181</FONT>             * @param unsorted Input observations.<a name="line.181"></a>
<FONT color="green">182</FONT>             * @return the input observations, sorted.<a name="line.182"></a>
<FONT color="green">183</FONT>             */<a name="line.183"></a>
<FONT color="green">184</FONT>            private WeightedObservedPoint[] sortObservations(WeightedObservedPoint[] unsorted) {<a name="line.184"></a>
<FONT color="green">185</FONT>                final WeightedObservedPoint[] observations = unsorted.clone();<a name="line.185"></a>
<FONT color="green">186</FONT>                final Comparator&lt;WeightedObservedPoint&gt; cmp<a name="line.186"></a>
<FONT color="green">187</FONT>                    = new Comparator&lt;WeightedObservedPoint&gt;() {<a name="line.187"></a>
<FONT color="green">188</FONT>                    public int compare(WeightedObservedPoint p1,<a name="line.188"></a>
<FONT color="green">189</FONT>                                       WeightedObservedPoint p2) {<a name="line.189"></a>
<FONT color="green">190</FONT>                        if (p1 == null &amp;&amp; p2 == null) {<a name="line.190"></a>
<FONT color="green">191</FONT>                            return 0;<a name="line.191"></a>
<FONT color="green">192</FONT>                        }<a name="line.192"></a>
<FONT color="green">193</FONT>                        if (p1 == null) {<a name="line.193"></a>
<FONT color="green">194</FONT>                            return -1;<a name="line.194"></a>
<FONT color="green">195</FONT>                        }<a name="line.195"></a>
<FONT color="green">196</FONT>                        if (p2 == null) {<a name="line.196"></a>
<FONT color="green">197</FONT>                            return 1;<a name="line.197"></a>
<FONT color="green">198</FONT>                        }<a name="line.198"></a>
<FONT color="green">199</FONT>                        if (p1.getX() &lt; p2.getX()) {<a name="line.199"></a>
<FONT color="green">200</FONT>                            return -1;<a name="line.200"></a>
<FONT color="green">201</FONT>                        }<a name="line.201"></a>
<FONT color="green">202</FONT>                        if (p1.getX() &gt; p2.getX()) {<a name="line.202"></a>
<FONT color="green">203</FONT>                            return 1;<a name="line.203"></a>
<FONT color="green">204</FONT>                        }<a name="line.204"></a>
<FONT color="green">205</FONT>                        if (p1.getY() &lt; p2.getY()) {<a name="line.205"></a>
<FONT color="green">206</FONT>                            return -1;<a name="line.206"></a>
<FONT color="green">207</FONT>                        }<a name="line.207"></a>
<FONT color="green">208</FONT>                        if (p1.getY() &gt; p2.getY()) {<a name="line.208"></a>
<FONT color="green">209</FONT>                            return 1;<a name="line.209"></a>
<FONT color="green">210</FONT>                        }<a name="line.210"></a>
<FONT color="green">211</FONT>                        if (p1.getWeight() &lt; p2.getWeight()) {<a name="line.211"></a>
<FONT color="green">212</FONT>                            return -1;<a name="line.212"></a>
<FONT color="green">213</FONT>                        }<a name="line.213"></a>
<FONT color="green">214</FONT>                        if (p1.getWeight() &gt; p2.getWeight()) {<a name="line.214"></a>
<FONT color="green">215</FONT>                            return 1;<a name="line.215"></a>
<FONT color="green">216</FONT>                        }<a name="line.216"></a>
<FONT color="green">217</FONT>                        return 0;<a name="line.217"></a>
<FONT color="green">218</FONT>                    }<a name="line.218"></a>
<FONT color="green">219</FONT>                };<a name="line.219"></a>
<FONT color="green">220</FONT>    <a name="line.220"></a>
<FONT color="green">221</FONT>                Arrays.sort(observations, cmp);<a name="line.221"></a>
<FONT color="green">222</FONT>                return observations;<a name="line.222"></a>
<FONT color="green">223</FONT>            }<a name="line.223"></a>
<FONT color="green">224</FONT>    <a name="line.224"></a>
<FONT color="green">225</FONT>            /**<a name="line.225"></a>
<FONT color="green">226</FONT>             * Guesses the parameters based on the specified observed points.<a name="line.226"></a>
<FONT color="green">227</FONT>             *<a name="line.227"></a>
<FONT color="green">228</FONT>             * @param points Observed points, sorted.<a name="line.228"></a>
<FONT color="green">229</FONT>             * @return the guessed parameters (normalization factor, mean and<a name="line.229"></a>
<FONT color="green">230</FONT>             * sigma).<a name="line.230"></a>
<FONT color="green">231</FONT>             */<a name="line.231"></a>
<FONT color="green">232</FONT>            private double[] basicGuess(WeightedObservedPoint[] points) {<a name="line.232"></a>
<FONT color="green">233</FONT>                final int maxYIdx = findMaxY(points);<a name="line.233"></a>
<FONT color="green">234</FONT>                final double n = points[maxYIdx].getY();<a name="line.234"></a>
<FONT color="green">235</FONT>                final double m = points[maxYIdx].getX();<a name="line.235"></a>
<FONT color="green">236</FONT>    <a name="line.236"></a>
<FONT color="green">237</FONT>                double fwhmApprox;<a name="line.237"></a>
<FONT color="green">238</FONT>                try {<a name="line.238"></a>
<FONT color="green">239</FONT>                    final double halfY = n + ((m - n) / 2);<a name="line.239"></a>
<FONT color="green">240</FONT>                    final double fwhmX1 = interpolateXAtY(points, maxYIdx, -1, halfY);<a name="line.240"></a>
<FONT color="green">241</FONT>                    final double fwhmX2 = interpolateXAtY(points, maxYIdx, 1, halfY);<a name="line.241"></a>
<FONT color="green">242</FONT>                    fwhmApprox = fwhmX2 - fwhmX1;<a name="line.242"></a>
<FONT color="green">243</FONT>                } catch (OutOfRangeException e) {<a name="line.243"></a>
<FONT color="green">244</FONT>                    // TODO: Exceptions should not be used for flow control.<a name="line.244"></a>
<FONT color="green">245</FONT>                    fwhmApprox = points[points.length - 1].getX() - points[0].getX();<a name="line.245"></a>
<FONT color="green">246</FONT>                }<a name="line.246"></a>
<FONT color="green">247</FONT>                final double s = fwhmApprox / (2 * FastMath.sqrt(2 * FastMath.log(2)));<a name="line.247"></a>
<FONT color="green">248</FONT>    <a name="line.248"></a>
<FONT color="green">249</FONT>                return new double[] { n, m, s };<a name="line.249"></a>
<FONT color="green">250</FONT>            }<a name="line.250"></a>
<FONT color="green">251</FONT>    <a name="line.251"></a>
<FONT color="green">252</FONT>            /**<a name="line.252"></a>
<FONT color="green">253</FONT>             * Finds index of point in specified points with the largest Y.<a name="line.253"></a>
<FONT color="green">254</FONT>             *<a name="line.254"></a>
<FONT color="green">255</FONT>             * @param points Points to search.<a name="line.255"></a>
<FONT color="green">256</FONT>             * @return the index in specified points array.<a name="line.256"></a>
<FONT color="green">257</FONT>             */<a name="line.257"></a>
<FONT color="green">258</FONT>            private int findMaxY(WeightedObservedPoint[] points) {<a name="line.258"></a>
<FONT color="green">259</FONT>                int maxYIdx = 0;<a name="line.259"></a>
<FONT color="green">260</FONT>                for (int i = 1; i &lt; points.length; i++) {<a name="line.260"></a>
<FONT color="green">261</FONT>                    if (points[i].getY() &gt; points[maxYIdx].getY()) {<a name="line.261"></a>
<FONT color="green">262</FONT>                        maxYIdx = i;<a name="line.262"></a>
<FONT color="green">263</FONT>                    }<a name="line.263"></a>
<FONT color="green">264</FONT>                }<a name="line.264"></a>
<FONT color="green">265</FONT>                return maxYIdx;<a name="line.265"></a>
<FONT color="green">266</FONT>            }<a name="line.266"></a>
<FONT color="green">267</FONT>    <a name="line.267"></a>
<FONT color="green">268</FONT>            /**<a name="line.268"></a>
<FONT color="green">269</FONT>             * Interpolates using the specified points to determine X at the<a name="line.269"></a>
<FONT color="green">270</FONT>             * specified Y.<a name="line.270"></a>
<FONT color="green">271</FONT>             *<a name="line.271"></a>
<FONT color="green">272</FONT>             * @param points Points to use for interpolation.<a name="line.272"></a>
<FONT color="green">273</FONT>             * @param startIdx Index within points from which to start the search for<a name="line.273"></a>
<FONT color="green">274</FONT>             * interpolation bounds points.<a name="line.274"></a>
<FONT color="green">275</FONT>             * @param idxStep Index step for searching interpolation bounds points.<a name="line.275"></a>
<FONT color="green">276</FONT>             * @param y Y value for which X should be determined.<a name="line.276"></a>
<FONT color="green">277</FONT>             * @return the value of X for the specified Y.<a name="line.277"></a>
<FONT color="green">278</FONT>             * @throws ZeroException if {@code idxStep} is 0.<a name="line.278"></a>
<FONT color="green">279</FONT>             * @throws OutOfRangeException if specified {@code y} is not within the<a name="line.279"></a>
<FONT color="green">280</FONT>             * range of the specified {@code points}.<a name="line.280"></a>
<FONT color="green">281</FONT>             */<a name="line.281"></a>
<FONT color="green">282</FONT>            private double interpolateXAtY(WeightedObservedPoint[] points,<a name="line.282"></a>
<FONT color="green">283</FONT>                                           int startIdx,<a name="line.283"></a>
<FONT color="green">284</FONT>                                           int idxStep,<a name="line.284"></a>
<FONT color="green">285</FONT>                                           double y)<a name="line.285"></a>
<FONT color="green">286</FONT>                throws OutOfRangeException {<a name="line.286"></a>
<FONT color="green">287</FONT>                if (idxStep == 0) {<a name="line.287"></a>
<FONT color="green">288</FONT>                    throw new ZeroException();<a name="line.288"></a>
<FONT color="green">289</FONT>                }<a name="line.289"></a>
<FONT color="green">290</FONT>                final WeightedObservedPoint[] twoPoints<a name="line.290"></a>
<FONT color="green">291</FONT>                    = getInterpolationPointsForY(points, startIdx, idxStep, y);<a name="line.291"></a>
<FONT color="green">292</FONT>                final WeightedObservedPoint p1 = twoPoints[0];<a name="line.292"></a>
<FONT color="green">293</FONT>                final WeightedObservedPoint p2 = twoPoints[1];<a name="line.293"></a>
<FONT color="green">294</FONT>                if (p1.getY() == y) {<a name="line.294"></a>
<FONT color="green">295</FONT>                    return p1.getX();<a name="line.295"></a>
<FONT color="green">296</FONT>                }<a name="line.296"></a>
<FONT color="green">297</FONT>                if (p2.getY() == y) {<a name="line.297"></a>
<FONT color="green">298</FONT>                    return p2.getX();<a name="line.298"></a>
<FONT color="green">299</FONT>                }<a name="line.299"></a>
<FONT color="green">300</FONT>                return p1.getX() + (((y - p1.getY()) * (p2.getX() - p1.getX())) /<a name="line.300"></a>
<FONT color="green">301</FONT>                                    (p2.getY() - p1.getY()));<a name="line.301"></a>
<FONT color="green">302</FONT>            }<a name="line.302"></a>
<FONT color="green">303</FONT>    <a name="line.303"></a>
<FONT color="green">304</FONT>            /**<a name="line.304"></a>
<FONT color="green">305</FONT>             * Gets the two bounding interpolation points from the specified points<a name="line.305"></a>
<FONT color="green">306</FONT>             * suitable for determining X at the specified Y.<a name="line.306"></a>
<FONT color="green">307</FONT>             *<a name="line.307"></a>
<FONT color="green">308</FONT>             * @param points Points to use for interpolation.<a name="line.308"></a>
<FONT color="green">309</FONT>             * @param startIdx Index within points from which to start search for<a name="line.309"></a>
<FONT color="green">310</FONT>             * interpolation bounds points.<a name="line.310"></a>
<FONT color="green">311</FONT>             * @param idxStep Index step for search for interpolation bounds points.<a name="line.311"></a>
<FONT color="green">312</FONT>             * @param y Y value for which X should be determined.<a name="line.312"></a>
<FONT color="green">313</FONT>             * @return the array containing two points suitable for determining X at<a name="line.313"></a>
<FONT color="green">314</FONT>             * the specified Y.<a name="line.314"></a>
<FONT color="green">315</FONT>             * @throws ZeroException if {@code idxStep} is 0.<a name="line.315"></a>
<FONT color="green">316</FONT>             * @throws OutOfRangeException if specified {@code y} is not within the<a name="line.316"></a>
<FONT color="green">317</FONT>             * range of the specified {@code points}.<a name="line.317"></a>
<FONT color="green">318</FONT>             */<a name="line.318"></a>
<FONT color="green">319</FONT>            private WeightedObservedPoint[] getInterpolationPointsForY(WeightedObservedPoint[] points,<a name="line.319"></a>
<FONT color="green">320</FONT>                                                                       int startIdx,<a name="line.320"></a>
<FONT color="green">321</FONT>                                                                       int idxStep,<a name="line.321"></a>
<FONT color="green">322</FONT>                                                                       double y)<a name="line.322"></a>
<FONT color="green">323</FONT>                throws OutOfRangeException {<a name="line.323"></a>
<FONT color="green">324</FONT>                if (idxStep == 0) {<a name="line.324"></a>
<FONT color="green">325</FONT>                    throw new ZeroException();<a name="line.325"></a>
<FONT color="green">326</FONT>                }<a name="line.326"></a>
<FONT color="green">327</FONT>                for (int i = startIdx;<a name="line.327"></a>
<FONT color="green">328</FONT>                     idxStep &lt; 0 ? i + idxStep &gt;= 0 : i + idxStep &lt; points.length;<a name="line.328"></a>
<FONT color="green">329</FONT>                     i += idxStep) {<a name="line.329"></a>
<FONT color="green">330</FONT>                    final WeightedObservedPoint p1 = points[i];<a name="line.330"></a>
<FONT color="green">331</FONT>                    final WeightedObservedPoint p2 = points[i + idxStep];<a name="line.331"></a>
<FONT color="green">332</FONT>                    if (isBetween(y, p1.getY(), p2.getY())) {<a name="line.332"></a>
<FONT color="green">333</FONT>                        if (idxStep &lt; 0) {<a name="line.333"></a>
<FONT color="green">334</FONT>                            return new WeightedObservedPoint[] { p2, p1 };<a name="line.334"></a>
<FONT color="green">335</FONT>                        } else {<a name="line.335"></a>
<FONT color="green">336</FONT>                            return new WeightedObservedPoint[] { p1, p2 };<a name="line.336"></a>
<FONT color="green">337</FONT>                        }<a name="line.337"></a>
<FONT color="green">338</FONT>                    }<a name="line.338"></a>
<FONT color="green">339</FONT>                }<a name="line.339"></a>
<FONT color="green">340</FONT>    <a name="line.340"></a>
<FONT color="green">341</FONT>                // Boundaries are replaced by dummy values because the raised<a name="line.341"></a>
<FONT color="green">342</FONT>                // exception is caught and the message never displayed.<a name="line.342"></a>
<FONT color="green">343</FONT>                // TODO: Exceptions should not be used for flow control.<a name="line.343"></a>
<FONT color="green">344</FONT>                throw new OutOfRangeException(y,<a name="line.344"></a>
<FONT color="green">345</FONT>                                              Double.NEGATIVE_INFINITY,<a name="line.345"></a>
<FONT color="green">346</FONT>                                              Double.POSITIVE_INFINITY);<a name="line.346"></a>
<FONT color="green">347</FONT>            }<a name="line.347"></a>
<FONT color="green">348</FONT>    <a name="line.348"></a>
<FONT color="green">349</FONT>            /**<a name="line.349"></a>
<FONT color="green">350</FONT>             * Determines whether a value is between two other values.<a name="line.350"></a>
<FONT color="green">351</FONT>             *<a name="line.351"></a>
<FONT color="green">352</FONT>             * @param value Value to test whether it is between {@code boundary1}<a name="line.352"></a>
<FONT color="green">353</FONT>             * and {@code boundary2}.<a name="line.353"></a>
<FONT color="green">354</FONT>             * @param boundary1 One end of the range.<a name="line.354"></a>
<FONT color="green">355</FONT>             * @param boundary2 Other end of the range.<a name="line.355"></a>
<FONT color="green">356</FONT>             * @return {@code true} if {@code value} is between {@code boundary1} and<a name="line.356"></a>
<FONT color="green">357</FONT>             * {@code boundary2} (inclusive), {@code false} otherwise.<a name="line.357"></a>
<FONT color="green">358</FONT>             */<a name="line.358"></a>
<FONT color="green">359</FONT>            private boolean isBetween(double value,<a name="line.359"></a>
<FONT color="green">360</FONT>                                      double boundary1,<a name="line.360"></a>
<FONT color="green">361</FONT>                                      double boundary2) {<a name="line.361"></a>
<FONT color="green">362</FONT>                return (value &gt;= boundary1 &amp;&amp; value &lt;= boundary2) ||<a name="line.362"></a>
<FONT color="green">363</FONT>                    (value &gt;= boundary2 &amp;&amp; value &lt;= boundary1);<a name="line.363"></a>
<FONT color="green">364</FONT>            }<a name="line.364"></a>
<FONT color="green">365</FONT>        }<a name="line.365"></a>
<FONT color="green">366</FONT>    }<a name="line.366"></a>




























































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